CN101111206A

CN101111206A - Cervical intervertebral prostheses

Info

Publication number: CN101111206A
Application number: CNA2005800473057A
Authority: CN
Inventors: A·凯勒
Original assignee: Waldemar Link GmbH and Co KG
Current assignee: Waldemar Link GmbH and Co KG
Priority date: 2005-01-26
Filing date: 2005-09-19
Publication date: 2008-01-23
Anticipated expiration: 2025-09-19
Also published as: CA2594454A1; JP4551929B2; US20060167552A1; RU2381771C2; BRPI0519969A2; TW200626115A; EP1685811A1; EP1841386A1; ATE509596T1; RU2007131557A; AU2005325807A1; CN100591306C; KR20070115900A; IL184373A0; ZA200706362B; US20120083891A1; JP2008528142A; WO2006079366A1; AR055497A1; MX2007008896A

Abstract

Disclosed is a cervical intervertebral prosthesis comprising two connecting plates (1, 5) that are to be attached to one of the adjacent vertebral bodies, respectively, and a joint core (20). Said joint core (20) forms a joint along with one connecting plate (1), said joint being provided with a concave joint surface (11) on the joint core (20) and a complementary convex joint surface on the connecting plate (1). The joint core (20) rests on the other connecting plate (5) via a sliding surface (17) which extends substantially parallel to the direction of the connecting plate (5), makes a relative movement in said direction possible, and is surrounded by an edge (15) that limits said relative movement. The concave joint surface (11) encompasses the convex joint surface at a solid angle (28) of at least 90 DEG . The section of the concave joint surface (11) which lies inside said solid angle lies within the recess (16) that is enclosed by the edge (15), thus increasing the stability of the prosthesis relative to laterally applied forces.

Description

The intervertebral prostheses of cervical region

The known intervertebral prostheses (US6368350) that a kind of cervical region is arranged, it is made up of the upper junction plate that is used to connect the adjacent ridge vertebral body and lower connecting plate and joint core (Gelenkkern), joint core and a connecting plate form the joint, and this joint is by being formed at protruding articular surface on the bottom surface of upper junction plate and the recessed articular surface on the end face of joint core.The joint core is supported on another connecting plate by sliding surface, and this sliding surface is parallel to the dimension of connecting plate and extends, and allows the joint core that the relative motion of translation is arranged with respect to lower connecting plate on this direction.This relative motion limits in this wise: sliding surface is lived by edge limitation vertically upward.The articular surface of joint core is configured to flat clamshell shape in known prosthese.This uses always, because can realize little particular surface load like this.But also bring following danger, promptly when the ligament of relevant vertebral body connection is too weak or elongation, the prosthese parts are disengagement mutually just.Known though (US-A-5895428), by the screw by articular surface medially the prosthese parts are connected with each other, but this can not link mutually with the translation freedom of movement recited above, that be parallel to the connecting plate yardstick of joint core, and in addition for cervical prosthesis, because limited space also is impossible.

Thereby task of the present invention provides a kind of prosthese that starts described type, even it also has competent stability when ligament is more weak.Solution is among the feature of independent claims and is preferred in the feature of dependent claims.

Stipulate thus: recessed articular surface surrounds the articular surface of projection with at least 90 ° space angle.Therefore guarantee: the power of effect can make the articular surface of projection can not skid off in recessed articular surface from the side obliquely.Because described angle determined recessed articular surface and surrounded the zone of articular surface of projection, so this angle is hereinafter referred to as angle of contact.This angle of contact is at least 110 ° aptly, more preferably 135 °.If it surpasses 180 ° according to another feature of the present invention, so Tu Qi articular surface just is completely fixed in the recessed articular surface.It is measured that angle of contact or space angle are used as the central angle of the circular cone between the radius, and these radiuses are from the point of the mutual face-off at the edge of recessed articular surface.

Because in the articular surface zone, be futile to the stable of prosthese, if joint core and other connecting plates be connected and unstable, so the present invention also stipulates: the part that is at least 90 ° the space angle of recessed articular surface is placed in the dimple that is surrounded by the edge.In other words, this part of articular surface is positioned under the plane that last seamed edge strutted by the edge.The joint core can not come out from lifting in the dimple of the connecting plate of being correlated with enough probability for the power of side action.As top advantageously described, if select to surpass 90 ° angle of contact, the exceeding 90 ° part and neither be positioned in the dimple of so recessed articular surface.Yet, be favourable like this.

The location of articular surface in dimple of projection not only is used to make the joint core to remain on and is fixedly coupled plate, and also be used to reduce the structure height of prosthese.The radius of projection articular surface gets so little with respect to the cross-sectional configurations of joint core, make the major part of articular surface all be positioned at the joint core, by within that part that dimple surrounded of lower connecting plate.The joint core can be constructed like this, makes it be positioned at dimple basically all.Yet can be provided with flange, this flange places on the edge of dimple in the above, takes place directly to contact so that avoid the metal part of upper junction plate and lower connecting plate to divide when arthrogryposis.

Half of articular surface radius that dimple should reach 1/3rd at least, preferably reach about joint core admitted the joint core.Preferred especially a kind of form of implementation, wherein the dimple mid point height that reaches the articular surface of joint core is basically admitted the joint core.The minimum constructive height of edge on sliding surface that surrounds dimple should reach at least dimple the Ap yardstick 1/4th, preferably reach 1/3rd at least.Abbreviation Ap represents fore-and-aft direction (antero-posterior).

By the combined effect at joint core and dimple edge, can desirable mode pre-determine the freedom of motion of joint core.In a kind of favourable embodiment, dimple is defined as rectangle, and is preferably square, and its border is parallel to and is transverse to the Ap direction.This has the following advantages: the dimple of maximum possible size can be placed in the lower connecting plate.In first kind of flexible program of this embodiment, can use to be defined as orthogonal joint core, this joint core has the side edge length shorter than dimple in one direction, and other side edge length of joint core are consistent basically with the side edge length of dimple.Therefore realized according to the orientation of joint core in dimple, the freedom of motion of joint core can be limited to (this is the most frequent situation) on the Ap direction or be limited on the direction perpendicular to the Ap direction.If in another flexible program, will avoid the translational motion of joint core fully, use the foursquare joint core that has identical size with dimple so.On the contrary, if wish on all directions freedom of motion to be arranged, that just selects the size of joint core on all directions all less than the size of dimple.

Below the present invention is described in detail with reference to the accompanying drawings.Accompanying drawing illustrates:

The longitudinal sectional view of Fig. 1 first embodiment;

The longitudinal sectional view of Fig. 2 second embodiment;

Two connecting plates of Fig. 3 are together with the decomposition diagram of therebetween multi-form joint core.

First connecting plate 1 has surface 2, and it is used for being connected with the cover plate of first vertebral body.Connecting plate can be provided with tooth or other device, is used for closely being connected with osseous tissue.The flange 3 of abdominal part comprises screwed hole 4, is used for bone screw.Self-evident, these CONSTRUCTED SPECIFICATIONs of prosthese can be configured to different.Second cover plate 5 has surface 6, is used for being connected with second vertebral body, and second cover plate 5 also has the abdominal part flange 7 with screwed hole 8.First connecting plate 1 illustrates in the above, and above also being applied in mostly.Therefore it is called as upper junction plate below, and another then is called lower connecting plate.But also can arrange conversely.

There is ball and socket joint 10 bottom surface of upper junction plate, and this ball and socket joint forms the articular surface that has mid point 12 11 of projection.Lower connecting plate 5 has the edge 15 that centers on, and it surrounds a foursquare dimple 16 on flat sliding surface 17.The inner surface at edge 15 is perpendicular to the sliding surface 17 of the bottom that has formed dimple 16 and be parallel to or extend perpendicular to the Ap direction.Turning 18 is roundings, on the Ap direction or perpendicular to the size the 26, the 27th of Ap direction,

identical.Connecting plate

1,5 is aptly by there being competent material to make, as metal.

Joint core 20 is positioned at dimple 16, and this joint core 20 is made by polyethylene, pottery or other material that helps sliding aptly.This joint core has smooth bottom surface, and this bottom surface is supported on the sliding surface 17 as far as possible in large area, and is formed for the sliding bearing of translational motion with this sliding surface 17.The joint core in Ap side upwardly extending side 21 and with it the side 22 of traversed by form orthogonal border, this border complementally is similar to the inner surface at the edge 15 of dimple 16.

Joint core 20 on top edge has flange 25, and it is arranged on the last seamed edge at edge 15.When curvature movement, this flange prevents that the bottom surface direct collision of upper junction plate 1 is on the part of lower connecting plate 5.24 li of side regions between connecting

plate

1,5 leave enough spaces and are used for relative curvature movement.

Joint core 20 includes spheric pit, and this pit complementally articular surface 11 with projection is identical, and constitutes accessory recessed articular surface.The mid point 12 of this pit overlaps with the mid point of the articular surface 11 of projection.Pit surrounds the articular surface 11 of projection in greater than 180 ° angle of contact.On mid point 12, pit narrows down a little, makes ball and socket joint 10 only just can leave this pit when strain, and is firmly remained in this pit under normal power effect thus.

Because the recessed articular surface 11 of joint core 20 most ofly surrounds ball and socket joint 10, even when therefore power occurring in the side, bending joint also has the stability of height.Joint core 20 equally also keeps in the dimple 16 by edge 15 with the stability of height.This is fully to be surrounded by edge 15 owing to joint core 20 is close to, and is surrounded by edge 15 on sizable height at least.The last seamed edge of joint core and be higher than the mid point 12 of recessed articular surface 11 by the plane 23 that seamed edge strutted on this.The height 29 of edge 15 on sliding surface 17 be slightly larger than dimple 16 Ap size 26 2/5ths.Even the joint core will lift slightly owing to unforeseen power, the joint core also always turns back on the position that illustrates by edge 15.

Connecting

plate

1,5 can make up with the joint core with different sides length.This is shown in Figure 3.The lateral size of joint core " a " identical with the inner surface at edge 15 (suitable gap is arranged).If the joint core is encased in 16 li of the dimples of lower connecting plate, the joint core does not just have the activity probability relatively of translation with respect to lower connecting plate 5 so.If therefore prosthese must be born the stable of articuli intervertebrales, that just uses this joint core when ligament weakens.

Joint core " c " is on the Ap direction and be transverse on the Ap direction less than dimple 16, and therefore on all directions, the motion probability all is restricted.This joint core has under the situation of certain translational motion distance in the expectation joint to be used, but still expects to reach stable this move distance after.

Joint core " b " is a kind of compromise proposal between such scheme, because the side edge length of the side 21 of joint core equates with the

side edge length

26,27 of dimple 16, and it is shorter to be transverse to the paired side 22 of extending this side.This means that joint core b is not mobilizable with respect to affiliated lower connecting plate 5, but then can move with limitation on the direction of side 22 on the direction of side 21.If stability in different directions needs difference, use this joint core so.Activeness is arranged on the Ap direction mostly, and connection in a lateral direction then is fixed.Yet also can realize opposite scheme.

Fig. 2 illustrates an embodiment, and it is with the different of embodiment among Fig. 1: the more articular surface 11 ' and the lower joint core 20 ' of flat structure.Angle of contact 28 ' has only about 110 °.Articular surface 11 ' by the determined zone of this angle of contact fully in dimple 16 ', that is to say not to be higher than interface, top 23 '.The radius 30 of articular surface surpasses 1/3rd and be positioned at dimple 16 ' under boundary face 23 ' with its section 31.The height 29 ' of dimple 16 ' be substantially equal to dimple the Ap size 1/3rd.The total height of prosthese is slightly less than the total height among first embodiment.It has high lateral stability equally.

Claims

1. the intervertebral prostheses of cervical region, have two connecting plates (1 that are used for being connected to separately on one of adjacent ridge vertebral body, 5), and has joint core (20,20 '), a this joint core and a connecting plate (1) form the joint, this joint is at joint core (20,20 ') has recessed articular surface (11 on, 11 ') and the articular surface that on described connecting plate (1), has complementally projection, and the sliding surface (17) that described joint core extends by the direction that is basically parallel to another connecting plate (5) is supported on this another connecting plate (5), this sliding surface allows on this direction relative motion is arranged, and the edge (15) that has been defined this relative motion centers on, and it is characterized in that, described recessed articular surface (11,11 ') surround with at least 90 ° space angle (28,28 ') articular surface projection, and this recessed articular surface (11,11 ') the part that is positioned at this space angle is positioned in the dimple (16,16 ') that is surrounded by edge (15).

2. according to the described intervertebral prostheses of claim 1, it is characterized in that described recessed articular surface (11) surrounds with at least 180 ° space angle (28) articular surface with projection.

3. according to claim 1 or 2 described intervertebral prostheses, it is characterized in that described dimple (16,16 ') reaches 1/3rd height of articular surface radius (30) at least joint core (20,20 ') is admitted.

4. according to the described intervertebral prostheses of claim 3, it is characterized in that described dimple (16) reaches the height of mid point (12) of the articular surface (11) of this joint core substantially joint core (20) is admitted.

5. according to each described intervertebral prostheses in the claim 1 to 4, it is characterized in that the height (29) at described edge round dimple (15) is at least 1/4th of yardstick (26) that this edge makes progress in front and back.

6. according to each described intervertebral prostheses in the claim 1 to 5, it is characterized in that described joint core (20) is positioned at dimple (16) basically fully.

7. according to the described intervertebral prostheses of claim 6, it is characterized in that described joint core (20) has the flange (25) that stops connecting plate (1,5) directly to contact when bending.

8. according to each described intervertebral prostheses in the claim 1 to 7, it is characterized in that described dimple (16) is orthogonal, and the parallel sided of this dimple in or extend perpendicular to fore-and-aft direction.

9. according to the described intervertebral prostheses of claim 8, it is characterized in that, described dimple (16) is foursquare, and can use and be defined as orthogonal joint core (b), the a pair of side (21) of this joint core has the side edge length (26 with dimple (16), 27) side edge length of basically identical, and another of this joint core has short side edge length to side (22).

10. according to the described intervertebral prostheses of claim 8, it is characterized in that, can use joint core (a) with basic identical size as dimple (16).

11., it is characterized in that described dimple (16) is defined as square according to the described intervertebral prostheses of claim 8, and can use and be defined as orthogonal joint core (b) that this joint core has than the littler side edge length of dimple (16) on both direction.